Strange heater voltages on Partridge transformer

[Sansteeth]

Hello there,
I'm working on a new project, I have a full set of Partridges transformers for it that was taken out of a Carlsbro amp.
I was checking the voltages on the secondary of the power transformer (unloaded), and while I'm getting 340VAC on the B+ winding, 33V on the bias winding (sounds a little low no?), I'm getting 17.5VAC on the heater winding 
The heater winding has a center tap so I checked both sides and I'm getting 3.17VAC on one side, I'm getting 15VAC on the other side.
Has anyone experienced that before? What could be the cause of that?

The transformers have been taken out of a functioning amp (Carlsbro 100TOP), bias was alright, didnt sound all that good but it was mostly working that it should. I was not expecting that

thanks!

[Latole]

Carlsbro top 100 schematic

http://www.chambonino.com/carlsbro/carl100top.html

[sluckey]

I'm getting 17.5VAC on the heater winding 
The heater winding has a center tap so I checked both sides and I'm getting 3.17VAC on one side, I'm getting 15VAC on the other side.

If I measured the heater winding voltages with my Fluke 87V, I'd declare the transformer defective.

Are you sure you are measuring correctly?

[Latole]

If I measured the heater winding voltages with my Fluke 87V, I'd declare the transformer defective.

Are you sure you are measuring correctly?
[/quote]

I agree

[mresistor]

I think you discovered why it wasn't working so well.

[Sansteeth]

Hey folks, thanks for your replies!

Are you sure you are measuring correctly?

I would think so, I measured the same way on other transformers, and I'm getting the right voltages on the heater winding, also the fact that I'm getting 3.17VAC on one side of the winding makes me think that I'm doing it correctly so something's out of whack on the other side of the winding, what can possibly cause that?
The heater wire on those Partridges is crazy, 13AWG solid core, you'd think nothing can go wrong with that...
On another related subject, I'm getting what looks like two center taps on the primary of the output transformer from the same amp, is that a common thing? I mean, to me it actually makes more sense that two wires would come out of the end of two windings but I've usually seen only one CT wire.

[pdf64]

The OT may have a bifilar wound primary.
The heater winding’s CT is not essential; in normal operation, it carries no load current. What’s the voltage across the full winding?
Is there any internal resistive path between the different windings?

[Sansteeth]

Hey thanks for chipping in!

The heater winding’s CT is not essential; in normal operation, it carries no load current. What’s the voltage across the full winding?

Across the whole heater winding, I'm getting 17.5VAC

Is there any internal resistive path between the different windings?

I'm not sure what you mean by that 

[Latole]

Hey thanks for chipping in!

 

Is there any internal resistive path between the different windings?

I'm not sure what you mean by that 

How many ohms between all wires from transformer ?

[Sansteeth]

  So I was not getting any continuity reading on any windings for the heater and I was like, that sounds off...
So I filed the tip of those 13awg wires a bit for better connection, and not only am I getting continuity but now I'm getting 6.3VAC across the winding... So I feel very embarrassed for wasting your time y'all...
So I guess I should have thought about enamel coating on those thick wires... The reason why I didn't think I was not making contact is because I was getting readings, 3.15VAC on one side and almost 15VAC on the other side and I feel the coating should just prevent me from getting any reading at all, let alone readings that make some sort of sense for half of it.
Anyways, thanks y'all for your help and sorry for the waste of time

[Latole]

Great to know everything is working.

You're not the only one. I often read on the forums that the authors claim to have done all the tests possible but after several discussions, it often turns out that these tests were not done well. Repairing electronics, without too much difficulty, requires theoretical knowledge that people learning by themselves have no doubts.

[Sansteeth]

You're totally right, experience is a big one too. I know I have to make those mistakes so I don't get caught making them again in the future.

In any case, thanks a lot! Partridge transformer's not dead, the owner is gonna be happy

[PRR]

With modern high-impedance meters, it is not impossible you could read "15V" just from capacitance through varnish. I can show you "59V" on the third wire of a 3-way light on my stairs. If I put even 100k across it the reading drops to a few volts, showing it is wee weak leakage not solid power.

[Sansteeth]

Thank you, I needed to hear that, won't get fooled again! (hopefully)

Thanks everyone for helping out